Abstract: A document image scanner for reading a scanned document multiple times at resolutions different from the scanned resolution without rescanning. A sensor scans the source document to generate a digitized image that is stored in a memory at a first resolution. An input shifter is coupled to the memory for receiving a first number of pixels per line of the digitized image from memory. A vertical scaling element is coupled to the memory for changing a first vertical resolution to a second vertical resolution as the digitized image is transferred to the input shifter from memory. An output shifter is coupled to the input shifter for receiving a second number of pixels per line of the digitized image from the input shifter, wherein the ratio of the second number to the first number is the scaling factor. A horizontal scaling element is coupled to the memory for changing a first horizontal resolution to a second horizontal resolution as the digitized image is transferred to the output shifter from the input shifter.

Abstract: A digital image processing system has a pipeline bus for transferring addresses and data in parallel among the components of the system, which include an image memory, an address generator and an intensity processor. The pipeline bus includes a pipeline address bus, a pipeline data bus, and a master timing bus. Through the use of handshake signals, the pipeline bus permits a free flow of pipelined data among the components at whatever rate is necessary to complete the particular processing task. Image data is transferred in the form of N.times.N pixel subimage blocks which can be addressed using a single address.